spermogonia, aecia

on Onoclea

gall

uredinia hypophyllous, mostly sub-epidermal. The urediniospores are extruded as a thread; they are short-stalked elliptic, distally tapering into a sharp beak. A second type of uredionospores is long-stalked and pyriform. The more or less globular, usually 4-celled teliospores are formed below the epidermis, scattered in the leaf mesophyll.